API TR 405:1995 pdf download.An Inhalation Oncogenicity Study of Commercial Hexane in Rats and Mice
Mean body weights and body weight gains in the exposed animals were not statistically different from control values in the male mice. consumption in the 9018 ppm group was lower than controls on 29 of the 35 measurements obtained over the duration of the study. In the females however, at 9018 ppm, body weight gain was reduced. The mean body weight in the 9018 ppm female group was significantly lower than control weights after week 29. By week 53 the 9018 ppm female mice weighed 14% less than the control mice. Similar to the males, mean food consumption values were not statistically different from control values in the mice exposed to the mid and low concentration of commercial hexane. However, in the 9018 ppm group, food consumption was lower than control values on 19 o f the first 20 food consumption measurements at the beginning of the study. liver masses and nodules among the females in the 9018 ppm group but not among the males. There was a slight dose related decrease in the incidence of cysts in the uterus. However, food Macroscopic examinations found an apparent treatment related increase in Microscopic examinations found a treatment related increase in hepatocellular neoplasms (adenoma and carcinoma) among females in the 9018 ppm group. Liver tumors among males were not treatment related. The incidence of liver tumors in the Group IV females is similar to the incidence in control males. Male mice of this strain have a higher spontaneous incidence o f hepatocellular’- tumors than females. There was also a treatment related decrease in the severity and a slight decrease in the incidence o f cystic endometrial hyperplasia of the uterus among the females in the 9018 ppm group. There was an increase in the incidence of pituitary proliferative changes (hyperplasia, adenoma and adenocarcinoma) among al 1 treated groups of females but not among males.
Animals were acclimated for 27 days (27 December 1989 – 23 January 1990). All animals were examined by the staff veterinarian during the acclimation period. A sentinel control group of 15 animals per sex was exposed along with the test animals to verify the health status of the test animals. Three animals per sex were sacrificed prestudy. Pretest differential white blood counts, gross necropsies were performed on all sentinel animals. The survi vi ng animals were euthanited and their carcasses were discarded at study termi nation. More animals than required for the study were purchased and equi 1 ibrated. Animal s considered unsuitable for the study on the basis of pretest physical examinations , outlying body weight and ophthalmoscopic examination were eliminated prior to random selection for group assignment.